Accommodation ladders on ships are usually stowed on deck in a space or chest arranged for this purpose, which means that the accommodation ladder has to be pivoted about 180.degree. from its stowing position to its operating position. It is for economical reasons not customary to arrange a crane on deck for active the accommodation ladder, but instead the operation of the ladder has been made by means of a fixed davit. It is through the Swedish Pat. No. 334,307 known to provide the davit with a centre of gravity balancing block, which by means of a manually operated or motor-driven mechanism is capable of pivoting the block between two positions allowing the center of gravity of the ladder to pass a vertical line through the pivot axle of the ladder, when the ladder is pivoted from a stowing and active position resp.
Movable spindles and devices for pivoting the block are, however, subjected to severe ferrous corrosion and require a frequent service for the prevention of rust and seizure. Besides these details constitute a complication and rise in price of the whole device and an instability factor if the service is not meticulous.
It has a long time been desirable to perform this operation during the swinging-in and out movement of the accommodation ladder without an external additional force and the purpose of the present invention is to provide a simple construction which practically requires no service and which makes the block to swing between the two positions without any external aids.
According to the invention it is proposed that the pivoting of the pulley is achieved by means of a member attached to the ladder and transmitting a pull to the pulley caused by the weight of the ladder during the downward movement thereof.
The invention also refers to a device for pivoting an accommodation ladder and which solves the above mentioned problems by the fact that the pulley is mounted at one arm of a two-armed link, which is pivoted about a horizontal shaft arranged between said arms, that the link is mounted in the davit and pivoted between its end positions by means of at least one member, e.g. a wire, attached to the ladder at the side remote from its pivot axle, the opposite end of which being connected to the other arm of the link.